On 31/05/2019 14:33, Dmitry Osipenko wrote: > 31.05.2019 11:26, Peter De Schrijver пишет: >> On Fri, May 24, 2019 at 06:32:45PM +0300, Dmitry Osipenko wrote: >>> Hello, >>> >>> This series primarily unifies the driver code across all Tegra SoC >>> generations. In a result the clocksources are allocated per-CPU on >>> older Tegra's and have a higher rating than the arch-timer, the newer >>> Tegra210 is getting support for microsecond clocksource and the driver's >>> code is getting much cleaner. Note that arch-timer usage is discouraged on >>> all Tegra's due to the time jitter caused by the CPU frequency scaling. >> >> I think the limitations are more as follows: >> >> Chip timer suffers cpu dvfs jitter can wakeup from cc7 >> T20 us-timer No Yes >> T20 twd timer Yes No? >> T30 us-timer No Yes >> T30 twd timer Yes No? >> T114 us-timer No Yes >> T114 arch timer No Yes >> T124 us-timer No Yes >> T124 arch timer No Yes >> T210 us-timer No Yes >> T210 arch timer No No >> T210 clk_m timer No Yes >> >> right? > > Doesn't arch timer run off the CPU clock? If yes (that's what I > assumed), then it should be affected by the DVFS. Otherwise I'll lower > the clocksource's rating for T114/124/132. > > TWD can't wake CPU from the power-down state, so it's a solid "No" for > TWD in the "can wakeup from cc7" column. Wouldn't make sense to rename the timer-tegra20.c to timer-tegra.c now ? -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
